summaryrefslogtreecommitdiff
path: root/lib/default.nix
blob: 80860597a8c871086cfa738c44049bc156579431 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
let
  inherit
    (builtins)
    attrNames
    hashFile
    fetchurl
    fromJSON
    listToAttrs
    mapAttrs
    readDir
    readFile
    replaceStrings
    toFile
    toJSON
    ;

  # loads data from a toml json given
  # the directory (dir) and filename (name)
  # string -> string -> attrset
  fromMod = dir: name: fromTOML (readFile "${dir}/${name}");

  # replaces `.pw.toml` extensions with `.jar`
  # to correct the store paths of jarfiles
  # string -> string
  fixupName = replaceStrings [".pw.toml"] [".jar"];

  # *pkgs*.fetchurl wrapper that downloads a
  # jarfile mod. pkgs.fetchurl is used over builtins
  # here since we have a checksum and can take advantage
  # of fixed output derivations
  # attrset -> string -> attrset -> store path
  mkMod = pkgs: name: mod:
    pkgs.fetchurl {
      name = fixupName name;
      inherit (mod) url sha256;
    };

  # maps each mod in our checksums.json format
  # to the store path of a fixed output derivation
  # attrset -> attrset
  genMods = pkgs:
    mapAttrs (mkMod pkgs);

  # this is probably what you're looking for if
  # you're a developer trying to use this in your modpack.
  # this is where you create a checksums file for end users
  # to put into mkPackwizPackages, so make sure you keep it up to
  # date!
  #
  # `dir` is a path to the folder containing your .pw.toml files
  # files for mods. make sure they are the only files in the folder
  #
  # path -> file
  mkChecksums = dir: let
    mods = readDir dir;

    getChecksum = name: url:
      hashFile "sha256" (fetchurl {
        name = fixupName name;
        inherit url;
      });

    toWrite =
      toJSON
      (mapAttrs (mod: _: let
          data = fromMod dir mod;
        in {
          inherit (data.download) url;
          sha256 = getChecksum mod data.download.url;
        })
        mods);
  in
    toFile "checksums-json" toWrite;
in {
  inherit mkChecksums;

  # this is probably what you're looking for if
  # you're an end user trying to implement a modpack in
  # your module.
  #
  # `pkgs` is an instance of nixpkgs for your system,
  # must at least contain `fetchurl`.
  #
  # `checksums` is a json file from an upstream modpack
  # containing the names, urls, and sha256sums of mods
  #
  # attrset -> path -> attrset
  mkPackwizPackages = pkgs: checksums: genMods pkgs (fromJSON (readFile checksums));

  # this creates an `apps` attribute for a flake
  # which runs a bash script to generate a checksums
  # file
  #
  # `pkgs` is an instance of nixpkgs for your system,
  # must at least contain `writeShellScriptBin`
  #
  # `dir` is a path to the folder containing your .pw.toml files
  # files for mods. make sure they are the only files in the folder
  #
  # attrset -> path -> attrset
  mkChecksumsApp = pkgs: dir: let
    inherit (pkgs) writeShellScriptBin;
    checksums = mkChecksums dir;
    name = "generate-checksums";
    script = writeShellScriptBin name ''
      cat ${checksums} > checksums.json
    '';
  in {
    type = "app";
    program = script.outPath + "/bin/${name}";
  };

  # this creates an attrset value for
  # minecraft-servers.servers.<server>.symlinks
  # attrset -> attrset
  mkModLinks = mods: let
    fixup = map (name: {
      name = "mods/" + fixupName name;
      value = mods.${name};
    }) (attrNames mods);
  in
    listToAttrs fixup;
}